Standard building practice in wood frame construction calls for the common rafter to be joined to the double top plate by notching the rafter according to the pitch of the roof and toe nailing the rafter to the top plate. Obviously, notching the rafter weakens it considerably and toe nailing is only as effective as the skill of the carpenter. If the rafter is made of metal or has an I shape or made from Micro-Lam lumber as by Trus Joist Corporation of Boise, Idaho, then the standard notching method cannot be used and some type of metal connector is required or the top plate must be formed with a plurality of beam raps or the entire top plate must be beveled to the same angle as the roof pitch.
Daniels, U.S. Pat. No. 1,657,243 teachs a metallic casting for joining a timber to a top plate. The device is not adjustable in the field for accommodating different roof pitches. The device has no positive restriction to prevent overturning nor is there any attachment to the upper side of the plate to prevent lateral movement. A different bracket would have to be cast at the factory for each different roof pitch.
Barnett, U.S. Pat. No. 2,477,163 discloses a method of attaching the top and bottom chords of a truss. The top chord must be cut at an angle. This device does not attach the truss to the top plate.
Nesbitt, U.S. Pat. No. 3,031,727 attaches the top and bottom chords of a truss together and to a support post but has no adjustment means for attaching top chords with different pitches.
Nelson, U.S. Pat. No. 3,184,800 is the first support used with common rafters known to applicant. This support is not acceptable by any building code since there is no seat support. All of the load is carried on the outer edge of the plate and across an edge line of the rafter. There is no uplift value as required in areas subject to hurricanes or high uplift winds. Finally, there is no control of the angle; either in the installation or after installation. The rafter is free to rotate.
Tracy, U.S. Pat. No. 3,333,875 shows a bracket in FIG. 2, but it is not clear how the device is constructed. Apparently, it is a welded bracket which would be too expensive for construction purposes. The device obviously cannot be adjusted for pitch and there does not appear to be any attachment to the side of the plate for uplift value.
Tracy, U.S. Pat. No. 3,423,898 teaches the use of a simple U-bracket. There is no seat; all the bearing being taken by the edge nails. This device would take a great many nails and be far too heavy for practical application. Such a device could not be used for installing Trus Joist Micro-Lam's.
Hustead, U.S. Pat. No. 3,749,428 illustrates the pin type of connector which is too expensive for common rafters and unusable for Trus Joist Micro-Lam beams.
Snow, U.S. Pat. No. 3,967,908 discloses a two piece bracket which still requires end cutting of the rafter since it provides no end bearing. Only the nails provide bearing support.
Prins, U.S. Pat. No. 4,015,399 illustrates an apparatus for securing a hat shaped roof member using a threaded bolt and a complicated bracket. Such a device is far too expensive except for a very special building type structure.
There are presently anchors available from connector manufacturers but they are limited to 2.times.6 and 2.times.8 members and are unsuitable for members such as the Micro-Lam made by Trus Joist. See Simpson Company 1981 Catalog, Page (26).